---
title: focusRectOfInterest
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avcapturedevice/focusrectofinterest
---

# focusRectOfInterest

The device’s current focus rectangle of interest, if it has one.

## Declaration

```swift
var focusRectOfInterest: CGRect { get set }
```

## Discussion

Discussion The value of this property is a CGRect determining the device’s focus rectangle of interest. Use this as an alternative to setting focusPointOfInterest, as it allows you to specify both a location and size. For example, a value of CGRectMake(0, 0, 1, 1) tells the device to use the entire field of view when determining the focus, while CGRectMake(0, 0, 0.25, 0.25) indicates the top left sixteenth, and CGRectMake(0.75, 0.75, 0.25, 0.25) indicates the bottom right sixteenth. Setting focusRectOfInterest throws an NSInvalidArgumentException if isFocusRectOfInterestSupported returns false. Setting focusRectOfInterest throws an NSInvalidArgumentException if your provided rectangle’s size is smaller than the minFocusRectOfInterestSize. Setting focusRectOfInterest throws an NSGenericException if you call it without first obtaining exclusive access to the device using lockForConfiguration(). Setting focusRectOfInterest updates the device’s focusPointOfInterest to the center of your provided rectangle of interest. If you later set the device’s focusPointOfInterest, the focusRectOfInterest resets to the default sized rectangle of interest for the new focus point of interest. If you change your activeFormat, the point of interest and rectangle of interest both revert to their default values. You can observe automatic changes to the device’s focusRectOfInterest by key-value observing this property. note: Setting focusRectOfInterest alone does not initiate a focus operation. After setting focusRectOfInterest, set focusMode to apply the new rectangle of interest.

## See Also

### Setting a focus rectangle of interest

- [isFocusRectOfInterestSupported](avfoundation/avcapturedevice/isfocusrectofinterestsupported.md)
- [minFocusRectOfInterestSize](avfoundation/avcapturedevice/minfocusrectofinterestsize.md)
- [defaultRectForFocusPoint(ofInterest:)](avfoundation/avcapturedevice/defaultrectforfocuspoint(ofinterest:).md)